Urban and peri-urban agriculture is one of the strategies that emerged on the path towards agri-food sustainability in cities. This paper aims at improving the knowledge of the soil properties in a peri-urban area and their agricultural potential to support ecosystems with biodiversity worth conserving. The study area was located in the mid-plain of the Segura River (SE Spain). Arable soil layer samples were collected at 68 points to assess the distribution of organic carbon and to study other indicators of soil quality. A Wilcoxon and Kruskal–Wallis test was conducted to compare between the types of soils present in the area (calcaric Fluvisols and calcaric Regosols) and soil uses (industrial, cultivated and abandoned). Statistical analysis indicates that there are significant differences (at the 0.05 significance level) between Fluvisols and Regosols (p value = 3.65 × 10⁻⁵). Regarding use, the abandoned Fluvisols presented an average value of 9.33 g kg⁻¹ of OC while the Fluvisols that are currently cultivated have a higher average content of OC (11.35 g kg⁻¹). For soils under industrial use, the average OC content is 5.13 g kg⁻¹. Spatial distribution of organic carbon in these soils depends on the type of soil and the human influence on them, including the use.